Sri Lankan authorities say suspected Tamil Tiger rebels set off two roadside bombs in the island's north, killing a soldier and injuring 10 other people.

Officials say Sunday's blasts took place in Vavuniya district which lies on the edge of government-controlled and rebel-held territories. Authorities say one soldier was killed in a roadside blast targeting military personnel. A second bomb planted in the same district wounded six civilians and four policemen.

In other violence, military officials say troops killed 21 rebels during clashes across the north on Saturday. A rebel spokesman denied the army's claim.

There was no independent confirmation of the casualties.

Violence on the island has escalated, particularly near rebel strongholds in the north, since the government withdrew from a ceasefire with the Tigers in January.

Tamil Tiger rebels have been fighting since 1983 to create an independent homeland for Sri Lanka's minority ethnic Tamils. The conflict has killed more than 70,000 people.